Display device for use on keyboards



FIG. 1 is a front perspective view of a display device for use on keyboards showing my new design;

FIG. 2 is a side view of the display device for use on keyboards;

FIG. 3 is a front view of the display device for use on keyboards; and,

FIG. 4 is a rear view of the display device for use on keyboards. 

The ornamental design for a display device for use on keyboards, as shown. 